Study of Variability and Association of Yield Attributing Traits in Durum Wheat Genotypes

Twenty advanced line durum genotypes were tested to assess the presence of significant variability for grain yield and yield attributing traits by using randomized complete block design with three replications for two years at research farm of Agriculture and Forestry University, Chitwan, Nepal. Mean sum of squares revealed highly significant differences among durum wheat genotypes for all traits investigated, suggesting the possibility of improving durum wheat for these traits. High heritability associated with high genetic gain was found on some traits namely; flag leaf area, 1000-kernel weight and days to heading indicates the presence of additive gene action in controlling these traits. Grain yield (GYLD), harvest index (HI), test weight (TW), days to maturity (DTM), spike length (SPKL) and peduncle length (PDNL) showed low genetic gain associated with high heritability indicates the presence of non-additive gene action in controlling related traits. Grain filling rate (GFR), harvest index, grain number per spike (GNPS), test weight, plant height (HT) and peduncle length were found significantly correlated with grain yield at both genotypic and phenotypic levels. Among these traits, grain filling rate, grain number per spike and test weight, had the maximum direct positive effect on grain yield, which can be used as effective traits for selection of superior genotypes.